Method and apparatus for folding a closure flap of an envelope

ABSTRACT

Closure flap folding apparatus includes a transfer cylinder with rows of vacuum ports extending longitudinally along the periphery, a delivery cylinder having a plurality of rows of peripheral vacuum ports extending longitudinally thereon in spaced relation to each other and an intermediate seal fold cylinder also having vacuum ports extending longitudinally thereon. The transfer cylinder and delivery cylinder have the same diameter and are arranged to rotate in the same direction at substantially the same peripheral speed. The seal fold cylinder is positioned between the transfer cylinder and delivery cylinder and is arranged to engage a portion of the envelope transferred thereto by the transfer cylinder and retain engagement of the portion of the envelope while folding of the seal or closure flap takes place. The delivery cylinder engages the body portion of the envelope and transfers the envelope to a collecting device. The seal fold cylinder rotates at the same peripheral speed as the transfer cylinder in a direction opposite thereto and at an exact multiple of the angular velocity of the transfer cylinder, as for example, the seal fold cylinder completes four revolutions to a single revolution of the transfer cylinder. A timing device and valves are provided to exert a suction through the vacuum ports on the seal fold cylinder only when the vacuum ports are in overlying relation with the preselected portion of the envelope blank. The closure flaps may be folded forwardly in overlying relation with the opening in the envelope, rearwardly into overlying relation with the front surface of the envelope, or the envelope may be transferred through the folding device with the closure flap in an open unfolded position.

United tates Patent [151 enemas Smithe et a1. Feb. 15, 1972 [54] METHODAND APPARATUS FUR with rows of vacuum ports extending longitudinallyalong the FOLDING A CLOSURE FLAP OF AN periphery, a delivery cylinderhaving a plurality of rows of ENVELOPE peripheral vacuum ports extendinglongitudinally thereon in spaced relation to each other and anintermediate seal fold [72] Inventors: Eliot S. Smithe, New York, N.Y.;Herbert cylinder also having vacuum ports extending longitudinally W.Helm, l-lollidaysburg, Pa. thereon. The transfer cylinder and deliverycylinder have the same diameter and are arranged to rotate in the samedirection at substantially the same peripheral speed. The seal foldcylinder is positioned between the transfer cylinder and [73] Assignee:F. L. Smithe Machine Company, Inc.,

Duncansville, Pa.

[22] Filed; May 6 1970 delivery cylinder and is arranged to engage aportion of the envelope transferred thereto by the transfer cylinder andretain PP 35,190 engagement of the portion of the envelope while foldingof the seal or closure flap takes place. The delivery cylinder engages52 us. Cl ..93/62, 270/68 the body emebpe and transfers the B3, 21/26 acollecting device. The seal fold cylinder rotates at the same [51] C]peripheral speed as the transfer cylinder in a direction op- [58]FieldoiSearch ..93/62,61;2'. 0/68 posite thereto and man exact multipleofthe angular velocity of the transfer cylinder, as for example, theseal fold cylinder [56] References cued completes four revolutions to asingle revolution of the transfer cylinder. A timing device and valvesare provided to UNITED STATES PATENTS exert a suction through the vacuumports on the seal fold 3,088,382 5/ 1963 Winkler et a1. ..93/62 cylinderonly when the vacuum ports are in overlying relation 3,116,668 1/1964Novick ..93/62 with the preselected portion of the envelope blank. Theclosure flaps may be folded forwardly in overlying relation with PrimaryExaminer Bemard Stickney the opening in the envelope, rearwardly intooverlying relation Attorney-Stanley J. Price, Jr. with the front surfaceof the envelope, or the envelope may be transferred through the foldingdevice with the closure flap in 57] ABSTRACT an open unfolded position.

Closure flap folding apparatus includes a transfer cylinder 12 Claims,17 Drawing Figures I L3 a l4 L l v ,8 26 44 42 4 24 I 6 a is l aPATENTEDFEB 15 1912 3.641 .883

SHEET 2 [IF 6 PATENTEBFEB 1 5 1912 3.641 ,883

sum 3 OF 6 METHOD AND APPARATUS FOR FOLDING A CLOSURE FLAP OF ANENVELOPE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to a method and apparatus for folding closure flapsand more particularly to a method and apparatus for folding closureflaps with a plurality of rotary cylinders.

2. Description of the Prior Art Envelopeand bagmaking machines includeapparatus for folding the closure flap after the side and bottom flapsof the envelope blank have been folded and adhesively secured to theenvelope body portion. The conventional known closure flap foldingdevices include belts, pressure rollers and the like which exertcompressive forces on the folded envelope while conveying the envelopethrough the closure flap folding portion of the machine. U.S. Pat. No.3,097,758 illustrates a typical pair of pressure rollers for engagingthe envelope blank therebetween prior to the folding operation.

The known flap-folding apparatus is designed for a single type of foldas, for example, the normal forward fold of the closure flap and is notreadily convertible to apparatus for providing a reverse fold of theclosure flap or for permitting the envelopes to be conveyed therethroughwithout folding the closure flap. There is a need for apparatus that maybe easily converted to provide normal or reverse folds of the closureflap or to deliver the envelopes with the closure flaps in an open,unfolded condition. There is also a need for a rotary cylindricalenvelope closure flap folding device that does not exert squeezingpressure forces on the envelope.

SUMMARY OF THE INVENTION This invention relates to apparatus for foldingthe closure flap of an envelope which comprises a transfer cylinder withvacuum ports extending longitudinally along a portion of the cylinderperiphery. A delivery cylinder is positioned in spaced parallel relationto the transfer cylinder and has a plurality of vacuum ports extendinglongitudinally along a portion of the cylinder periphery. The deliverycylinder and transfer cylinder rotate in the same direction atsubstantially the same angular velocity. A seal fold cylinder ispositioned parallel to and between the delivery cylinder and thetransfer cylinder. The seal fold cylinder has a diameter smaller thanthe transfer cylinder and vacuum ports extend longitudinally along aportion of the cylinder periphery. Drive means are provided to rotatethe seal fold cylinder at an exact multiple of the angular velocity ofthe transfer cylinder. The seal fold cylinder vacuum ports are arrangedto engage a portion of an envelope by suction while the envelope isengaged to the transfer cylinder by suction and to convey the envelopefrom the transfer cylinder to the delivery cylinder through a suitableguide means or folding device.

The method for folding an envelope closure flap includes engaging theleading edge of the envelope by suction on the periphery of a transfercylinder. The transfer cylinder is rotated to a position where theenvelope leading edge is adjacent to the buckle plate portion ofafolding mechanism. The closure flap of the envelope is engaged bysuction to the periphery of a seal fold cylinder positioned adjacent tothe transfer cylinder. The seal fold cylinder is rotated in a directionopposite to the transfer cylinder while the closure flap portion of theenvelope is engaged to the periphery of the seal fold cylinder tothereby fold the closure flap into overlying relation with the rearsurface of the envelope. The body portion of the envelope is engaged bysuction onto the periphery of a delivery cylinder that is positionedadjacent to the seal fold cylinder and rotated in a direction oppositeto the direction of the seal fold cylinder. The suction on the seal foldcylinder is released to permit the delivery cylinder to transfer theenvelope with the closure flap folded into overlying relation with therear surface of the envelope.

To obtain a reverse seal fold where the closure flap is foldedrearwardly over the front surface of the envelope, only the closure flapportion of the envelope is engaged by suction to the periphery of thetransfer cylinder. The transfer cylinder is rotated until the envelopebody portion folds back over the closure flap and the envelope bodyportion is engaged by suction onto the periphery of the seal foldcylinder. The seal fold cylinder then transfers the envelope with theclosure flap folded rearwardly thereon to the delivery cylinder wherethe front surface of the envelope and the rearwardly folded closure flapare engaged to the periphery of the delivery cylinder.

Accordingly, the principal object of this invention is to provide arotary closure flap folding apparatus that eliminates belts, pressurerollers and the like.

Another object of this invention is to provide closure flap foldingapparatus that may be easily converted from normal forward foldapparatus to reverse fold apparatus.

These and other objects and advantages of this invention will be morecompletely disclosed and described in the follow ing specification, theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A, 1B and 1C are schematicillustrations in elevation illustrating sequentially the manner in whichthe closure flap of an envelope is folded with the apparatusillustrated.

FIGS. 2A, 2B and 2C are similar to FIGS. 1A, 1B and 1C illustratingsequentially the manner in which a reverse fold is applied to a closureflap of an envelope with the apparatus illustrated.

FIGS. 3A, 3B and 3C are also similar to FIGS. 1A, 1B and 1C andillustrate the manner of delivering envelopes in an unfolded, open sealcondition.

FIGS. 4A, 4B and 4C illustrate the sequential steps for folding outsideside seam envelopes immediately before applying a normal fold to theclosure flap.

FIG. 5 is a top plan view partially in section of the seal foldapparatus illustrated schematically in FIGS. 1-3 inclusive. Portions ofthe cylinders are in section to illustrate the valving mechanism toprovide a suction in the vacuum ports.

FIG. 6 is a view in section taken along the line VI-VI of FIG. 5.

FIG. 7 is a view in section illustrating in detail a suitable blockingvalve for applying a suction to the vacuum ports of the seal foldcylinder.

FIG. 8 is a view in section taken along the line VIIl-VlIl of FIG. 5illustrating the valve ports for the seal fold cylinder.

FIG. 9 is a view in section taken along the line IXIX of FIG. 5illustrating the valving for the vacuum ports along the periphery of thecylinder. Schematically illustrated in FIGS. 8 and 9 is the conduitconnecting the valve ports of the delivery cylinder and the seal foldcylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT Normal Closure Flap FoldReferring to the drawings and particularly FIGS. 1A, 1B and 1C, there isillustrated schematically closure flap folding apparatus generallydesignated by the numeral 10 that includes a bottom flap foldingcylinder 12 and a transfer cylinder 14 positioned in parallel relationto each other. The cylinders 12 and 14 are suitably mounted in a framemember and drivingly connected to each other by gearing, as laterexplained in reference to FIG. 5.

The bottom flap folding cylinder 12 has a series of vacuum ports 16opening into the periphery of the cylinder and extending longitudinallytherealong. The ports 16 are connected to a passageway 18 within thecylinder and the passageway is in turn connected through suitablevalving to a source of suction or reduced pressure. The transfercylinder 14 similarly has pairs of spaced vacuum ports 20 and 22 openinginto the cylinder periphery and extending longitudinally thereon.Passageways 24 and 26 connect the respective vacuum ports 20 and 22 to avacuum source through suitable valving, as later explained. The bottomflap folding cylinder 12 is arranged to rotate in a clockwise directionas viewed in FIG. 1 and cylinder 14 is arranged to rotate in acounterclockwise direction and to engage and transfer an envelope blankfrom the bottom flap folding cylinder 12 to the remaining portion of theclosure flap folding apparatus 10.

A delivery cylinder 28 is also mounted in the machine frame in parallelspaced relation to the transfer cylinder 14 and has a series oflongitudinally extending vacuum ports 30, 32, 34 and 36 opening into andextending around the periphery of the cylinder. The vacuum ports 30, 32,34 and 36 are connected respectively to passageways 38, 40, 42, and 44that are in turn connected to a source of suction through valving, aslater explained, to progressively apply and withdraw suction to theperiphery of the cylinder 28 through the longitudinally extendingparallel rows of respective ports 30, 32, 34 and 36.

A seal fold cylinder 46 is rotatably mounted in the machine frame and ispositioned between the transfer cylinder 14 and the delivery cylinder28. The seal fold cylinder 46 has a single row of vacuum ports 48 alongthe periphery that are arranged to engage a portion of the envelopeblank and transfer the envelope blank to the delivery cylinder 28. Theseal fold cylinder 46 and delivery cylinder 28 are drivingly connectedin timed relation so that the angular velocity of the seal fold cylinder46 is an exact multiple of the angular velocity of the delivery cylinder28 as for example for each revolution of the delivery cylinder 28 theseal fold cylinder revolves four times. Bleeder valves and vacuum valvesare associated with the seal fold cylinder 46 to apply a suction throughthe vacuum ports 48 during one portion of the revolution of the sealfold cylinder 46 and to terminate the vacuum or suction during theremaining three revolutions of the cylinder 46. The delivery cylinder 28rotates in a counterclockwise direction, the same direction as thetransfer cylinder 14. The seal fold cylinder 46 rotates in a clockwisedirection, opposite to that of the delivery cylinder 28.

A buckle plate generally designated by the numeral 50 is positionedabove the seal fold cylinder 46 and has a longitudinal slot 52 and guideportion 54. The slot 52 has an end wall 56 against which the envelopeblank abuts when the envelope reverses direction. A suitable guidebracket 58 is positioned beneath the cylinders 14 and 28 and aconventional delivery spiral is rotatably positioned at the downstreamend from the delivery cylinder 28. The apparatus illustrated in FIGS.1A, 1B and 1C fold the closure flap 62 of an envelope generallydesignated by the numeral 64 that has a rear surface 66 (FIG. 1A) and afront surface 68 (FlG. 1C).

The apparatus illustrated in FIGS. 1A, 1B and 1C folds the closure flap62 in overlying relation with the rear surface 66 of the envelope in thefollowing manner. The top surface 68 of the envelope 64 is engaged bysuction through vacuum ports 16 to the periphery of the bottom flap foldcylinder. Upon rotation in a clockwise direction the undersurface 66 ofthe envelope is moved into overlying relation with the vacuum ports and22 on the transfer cylinder 14. Suction is applied through the ports 20and 22 to engage the envelope to the periphery of transfer cylinder 14.

The bottom flap fold cylinder 12 and transfer cylinder 14 are so timedthat the front edge or base of the envelope opposite the closure flap 62is in overlying relation with the vacuum ports 20 so that the closureflap 62 is not engaged to the cylinder 14 by suction. Rotation of thetransfer cylinder 14 rotates the transfer cylinder in a counterclockwisedirection to a location where the front edge of the envelope 64 isdisengaged from the transfer cylinder 14 and is conveyed upwardly in theslot 52 of buckle plate 50. As the envelope blank moves up into the slot52 the closure flap 62 is in overlying relation with the vacuum ports 48on the seal fold cylinder 46. Suction is applied through vacuum ports 48in the seal fold cylinder 46 to engage the closure flap 62. Rotation ofthe seal fold cylinder 46 in a clockwise direction folds the closureflap 62 along a score line, as illustrated in FIG. 2.

The delivery cylinder 28 rotates in timed relation with the transfercylinder 14 and seal fold cylinder 46 to move the vacuum ports 30, 32,34 and 36 into progressive overlying relation with portions of theenvelope front surface 68 and move the envelope 64 downwardly in theslot 52 and between the transfer cylinder 28 and seal fold cylinder 46with the folded closure flap 62 forming the leading edge of the envelope64. The envelope is transferred by the delivery cylinder 28 to aconventional delivery spiral 60 where the envelope is transferred intoan arcuate receiving slot 70 for delivery to a stack 72. It will thus beapparent with the above arrangement that it is now possible to apply anormal forward seal fold to closure flap 62 solely with rotatingcylinders and without pressure rollers, belts, tapes and the like. Thisarrangement is suitable for high-speed handling and folding of envelopesand may be used with puffed or thin airmail envelopes.

Reverse Fold Referring to FlGS. 2A. 2B and 2C, the seal foldingapparatus illustrated in FIGS. 1A, 1B and IC has been modified toreverse the seal fold rather than provide the normal fold previouslydescribed. Because substantially all of the apparatus illustrated inFIGS. 2A, 2B and 2C is the same as that illustrated in FIGS. 1A, 1B and1C, similar numerals will designate similar parts. The buckle plate 50and the guide bracket 58 are removed and another guide bracket 74 ispositioned in place of buckle plate 50. The timing of the transfercylinder 14 and the position of the vacuum ports 20 and 22 relative tothe envelope 64 is modified so that the closure flap portion 62 of theenvelope is engaged by vacuum through ports 20 and 22 to the peripheryof transfer cylinder 14. The remaining portion of the envelope 64 hangsdownwardly from the transfer cylinder 14 upon rotation as illustrated inFlG. 2A. Upon rotation of the transfer cylinder 14 the envelope 64 ismoved upwardly toward the seal fold cylinder 46. Vacuum through ports 48in seal fold cylinder 46 engages the rear surface 66 of envelope 64 andtransfers the envelope 64 to the delivery cylinder 28, as illustrated inFlGS. 2B and 2C. ln FlG. 2B the closure flap 62 is bent rearwardly overthe front surface 68 of envelope 64 and the envelope rear surface 66 isengaged by the vacuum ports 48 on the seal fold cylinder 46 adjacent thescore line for the closure flap 62. Rotation of the seal fold cylinder46 transfers the envelope 64 to the delivery cylinder 28 where theenvelope front surface 68 with the closure flap 62 folded rearwardlythereon is engaged by vacuum through the ports 30, 32, 34 and 36. Theenvelope with the rearwardly folded closure flap 62 is then transferredto a delivery spiral 60 and from the delivery spiral to a stack 72, aspreviously described.

It will be apparent by simply removing the buckle plate 50 and lowerguide 58 and replacing the buckle plate 50 with a second guide means 74and changing the timing of the transfer cylinder 14, it is possible tomodify the flap-folding apparatus from a normal closure flap fold to areverse closure flap fold. Since the folding of the envelope isaccomplished by rotary cylinders and the envelopes are engaged to thecylinders by means of vacuum, high-speed folding even the reverse sealfold is possible with this apparatus. The reverse seal fold is usefulwhere the envelopes are to be utilized in automated stuffing operations.

Open Seal Delivery For certain stuffing operations it is desirable toprovide envelopes wherein the closure flap is in an open, unfoldedcondition. The apparatus illustrated in FIGS. 2A, 2B and 2C may beemployed to transfer the envelopes through the folding apparatus withoutfolding the closure flap 62 either in the normal seal fold or thereverse seal fold. The undersurface 66 of the envelope 64 is engagedadjacent the edge opposite the closure flap 62 by the suction ports 20and 22 of the transfer cylinder 14 and rotated toward the guide member74 positioned above the seal fold cylinder 46. As illustrated in FlG.38, when the envelope 64 is disengaged from the periphery of transfercylinder 14 it is engaged to the periphery of seal fold cylinder 46 bymeans of suction through the vacuum ports 48. The seal fold cylinder 48serves as a transfer cylinder and transfers the leading edge of theenvelope 64 opposite the clo sure flap 62 to the delivery cylinder 28where the undersurface of the envelope is engaged to the periphery ofdelivery cylinder 28 by suction through vacuum ports 30, 32, 34 and 36.Rotation of the delivery cylinder 28 with the envelope secured theretoin a counterclockwise direction then transfers the envelope into a slot'70 of delivery spiral 60 from which it is positioned in a stack 72 withthe closure flaps 62 in an open position.

It will be apparent with the above apparatus that it is now possible toeither apply a reverse seal fold or to transfer envelopes in an openclosure flap condition to the delivery spiral with the same componentsof seal fold apparatus. The only requirement is the relative positionand timing of the seal fold cylinder 26.

Normal FoldOutside Side Seam Envelopes Referring to FIGS. 4A, 4B and 4C,there is illustrated seal fold apparatus suitable for use with envelopesthat includes a side flap folding apparatus in lieu of the transfercylinder previously described. In the apparatus illustrated in FIGS. 4A,4B and 4C, similar numerals will be used for similar parts. The sealfold apparatus generally designated by the numeral has a bottom flapfold cylinder 12 with a pressure roller 76 positioned in abuttingrelation therewith. Endless driven tapes or belts 78 are positionedaround rollers 80 and 82 and have a tensioning drive roll 84. A pair ofplowshare side flap fold devices 86 are positioned above the tapes 78.The seal fold cylinder 46 has vacuum ports 48, as previously described,and the buckle plate 50 is positioned above the seal fold cylinder 46and adjacent to the transfer cylinder 28.

As illustrated in FIG. 4A, the envelope blank 88 having a body portion90 with a front flap 92 and a pair of side flaps 94 and 96 and a rearclosure flap 98 has the front flap 92 bent rearwardly over the bodyportion and folded thereon as it is transferred from the bottom flapfolding cylinder 12 onto the belts 78. The plowshares 86 fold the sideflaps 94 and 96 into overlying relation with the bottom flap 92 to forman outside side seam type envelope. The belts 78 transfer the envelopeupwardly into the slot 52 of the buckle plate 50 and the closure flap 98is engaged to the periphery of seal fold cylinder 46 by suction throughthe vacuum ports 48. The seal fold cylinder 46 rotates in a clockwisedirection and the delivery cylinder 28 rotates in a counterclockwisedirection. The envelope body portion is engaged to the periphery of thedelivery cylinder by suction through vacuum ports 30, 32, 34 and 36 androtation of the seal fold cylinder 46 in a direction opposite to thedelivery cylinder 28 with the envelope therebetween folds the closureflap 48 into overlying relation with the side flaps 94 and 96 and bottomflap 92. The envelope is transferred in a similar manner to the spiral60 as was discussed in reference to FIG. 1.

With this arrangement it is now possible with minor substitutions andmodifications of the closure flap apparatus to provide apparatus forfolding the side flaps immediately prior to folding the closure flap ofthe envelope into overlying relation with the side flaps as a normalclosure flap fold. To modify the previously described apparatus thetransfer cylinder is removed and the tapes or belts 78 with their drivemeans substituted therefor and the plowshares positioned thereabove.

Referring to FIGS. 59, one arrangement of the cylinders and valves inthe seal fold apparatus 10 is illustrated. FIG. 5 is a top plan viewwith the direction of travel of the sheets being indicated by the arrowsand extending from the bottom toward the top of the sheet. The cylindersof the seal fold apparatus are rotatably journaled in the envelopemachine side frames 100 and 102. The bottom flap fold cylinder 12 has amain shaft 104 that is journaled in the side frames for rotationtherein. Gearing 106 on drive shaft 108 is in meshing relation with agear 110 on the bottom flap fold cylinder 104 to provide rotationthereto. The suction passageway 18 within the cylinder 12 has vacuumports 16 connected thereto. A valve generally designated by the numeral112 has a stationary por tion or stator 114 and a rotatable portion orrotor 116. The valve 112 is arranged to open and close the passageway 18in preselected portions of each revolution of the bottom flap foldcylinder 12 to thereby apply and remove negative suction pressure to theperiphery of the cylinder 12. FIG. 6 illustrates the bottom flap foldcylinder in section with the suction passageway 18 and the vacuum ports16.

The transfer cylinder 14 is rotatably mounted on a shaft 118 that issuitably journaled in bearings in subframe members 120. A spur gear 122on shaft 118 meshes with a spur gear 124 on shaft 104 of bottom flapfold cylinder 12 so that the transfer cylinder 14 is driven in timedrelation with the bottom flap fold cylinder 12. The transfer cylinder 14has a rotary valve generally designated by the numeral 126 that has astator portion 128 and a rotor portion 130. The inlet 132 to the stator128 supplies a suction to the pairs of vacuum ports 20 and 22 during apreselected portion of each revolution of the transfer cylinder 14, aspreviously described. The location at which the arcuate opening 134 inthe rotor is subjected to the vacuum through opening 132 may be changedby rotating the fixed stator 128 of valve 126.

In FIG. 7, there is illustrated one manner'of applying suction to thevacuum ports 48 of the seal fold cylinder 46 through an axial passageway138 in the seal fold cylinder 46 (FIG. 8). A valve generally designatedby the numeral 140 has a rotor portion 142 that may be suitably securedto a rotating portion of any one of cylinders 12, 14 or 28. The rotorhas an arcuate opening 144 therein and a stator 146 is positioned inoverlying relation therewith. The stator has a first opening or port 148connected to a source of vacuum such as a conventional vacuum pump (notshown) and a second port 150 suitably connected by a conduit 152 to theseal fold cylinder valve. With this arrangement, suction is appliedthrough the seal fold cylinder vacuum ports for about one-fourth of arevolution of the cylinder to which the valve 140 is connected.Throughout the other three-fourths of a revolution, the valve port 148is closed by the rotor 142 so that suction is not applied to the vacuumports 48 of the seal fold cylinder 46. Since the seal fold cylinderrotates at an exact multiple of the angular velocity of the othercylinder, suction is applied through the valve ports 48 of the seal foldcylinder 46 during one of the revolutions of the seal fold cylinder 46and suction is not present during several subsequent revolutions of theseal fold cylinder 46, depending on the multiple in the angular velocitybetween the respective cylinder. The above valve mechanism provides ameans for periodically applying a suction through valve ports 48 in theseal fold cylinder.

Referring to FIG. 5, the delivery cylinder 28 is rotatably mounted on ashaft 154 and is drivingly connected through gearing 156 and 158 to theshaft 160 of seal fold cylinder 46. The seal fold cylinder 46 anddelivery cylinder 28 are suitably journaled in hearings in subframes 162and 164. The delivery cylinder is, in turn, connected by gearing 166 and168 to a drive shaft of the envelope machine. As illustratedschematically in FlGS. 1-4, the delivery cylinder 28 has a plurality ofrows of vacuum ports 30, 32, 34 and 36 arranged in spaced relation alongthe periphery of the cylinder. The vacuum ports 30, 32, 34 and .36 openinto longitudinal passageways. A valve member generally designated bythe numeral 170 has a rotor portion 172 and a stator portion 174. Thestator 174 and rotor 172 are illustrated in FIG. 9.

The rotor 172 has a plurality of apertures 176 that are connected tounderlying passageways 38, 40, 42 and 44 in the delivery cylinder 28.Although there are a greater number of apertures 176 illustrated in FIG.9 than the passageways 38, 40, 42 and 44 illustrated in FIGS. 1-4, itshould be understood a fewer number of passageways and vacuum ports areillustrated in schematic drawings 14 for clarity and ease inunderstanding the operation of the envelopefolding apparatus.

The rotor 172, in addition to apertures 176, has an arcuate slottedportion 178. The stator 174 has an arcuate slotted portion 180 on thesame radius as the apertures 176 and a radially inwardly extendingportion 182 that has a portion on the same radius as the slot 178 in therotor portion 172. The stator has a port 184 connected to a suitablesource of vacuum and opening into slotted portion 180. The stator has asecond port 186 that is connected by means of a conduit 188diagrammatically illustrated in FIGS. 8 and 9. A shutoff valve 190 ispositioned in the conduit 183. With this arrangement, rotation of thecylinder 28 with the rotor 172 relative to the stator 174 will apply asuction through the rows of vacuum portions 30, 32, 34 and 36 as thepassageways 176 move into underlying relation with the arcuate slottedportion 180 in the stator 174. Similarly, suction is applied throughvacuum ports 148 in the seal fold cylinder 46 when the arcuate slottedportion 178 is in overlying relation with the port 186 in stator 174.Thus, suction is periodically applied through the row of vacuum ports 48in the seal fold cylinder 46 and in timed relation to the relativeangular position of the parallel spaced rows of valve ports in theperiphery of the delivery cylinder 28.

The arrangement illustrated in H6. 9 applies vacuum to both the deliverycylinder 28 and the seal fold cylinder 46 and is preferred. Where,however, it is desired to use separate valves for controlling the vacuumapplied by the delivery cylinder 28 and the seal fold cylinder 46, avalve similar to that illustrated in FIG. 7 may be connected to any ofthe other cylinders and used to control the periodic suction appliedthrough the row of valve ports 48 in the seal fold cylinder 46.

H0. 8 illustrates an adjusting mechanism for the valve on the seal foldcylinder 46. The cylinder 46 has a stator portion 192 with a port 194 towhich the conduit 188 is connected. The port 194 is connected to anarcuate slotted portion 196. The seal fold cylinder 46 extends throughthe sleevelike stator portion 192 and has an axial passageway 138 with aradial passageway 198 that opens into the arcuate passageway 196 ofstator 192. An adjusting screw 200 is suitably secured to the subframeand is arranged to rotate the stator 192 relative to the cylinder 46. Itwill be apparent, with the above valving arrangement that suction isapplied through the various rows of valve ports in timed relationbetween the respective cylinders to engage and transport the envelopeblanks through the envelope closure flap apparatus, as previouslydescribed.

Although the above apparatus was described with reference to folding aclosure flap of an envelope, it should be understood the above apparatusmay also be employed for folding various types of flaps on bags,envelopes and the like.

According to the provisions of the patent statutes, the principle,preferred construction and mode of operation of the invention have beenexplained, and what is considered to represent its best embodiment hasbeen illustrated and described. However, it should be understood that,within the scope of the appended claims, the invention may be practicedotherwise than as specifically illustrated and described.

We claim:

1. Apparatus for folding the closure flap of an envelope comprising,

a transfer device having means to engage and convey an envelope thereon,

a delivery cylinder positioned in spaced relation to said transferdevice, said delivery cylinder having a plurality of suction devicesextending longitudinally along the periphery of said cylinder,

a seal fold cylinder positioned parallel to said delivery cylinder andbetween said delivery cylinder and said transfer device, said seal foldcylinder having a diameter smaller than said delivery cylinder, saidseal fold cylinder having suction devices extending longitudinally alongthe periphery of said cylinder,

means to rotate said seal fold cylinder at a multiple of the angularvelocity of said delivery cylinder,

means to rotate said delivery cylinder in timed relation to said sealfold cylinder,

said seal fold cylinder suction devices arranged to engage a surface ofan envelope while said envelope is engaged by said transfer device andtransfer said envelope to said delivery cylinder, and

said delivery cylinder suction devices arranged to engage a surface ofsaid envelope and transfer said envelope away from said seal foldcylinder.

2. Apparatus for folding the closure flap of an envelope as set forth inclaim I in which,

said transfer device includes a transfer cylinder positioned in spacedparallel relation to said delivery cylinder,

said means to engage an envelope including suction devices extendinglongitudinally along the periphery of said transfer cylinder.

3. Apparatus for folding the closure flap of an envelope as set forth inclaim 1 which includes,

a buckle plate positioned adjacent to said seal fold cylinder,

said buckle plate having an elongated slot therein,

said buckle plate arranged to receive and support an envelope while saidseal fold cylinder engages the closure flap portion of said envelope andupon rotation of said seal fold cylinder folds said closure flap intooverlying relation with the rear surface of said envelope.

4. Apparatus for folding the closure flap of an envelope as set forth inclaim 1 comprising,

a guide bracket positioned above said seal fold cylinder, said guidebracket arranged to guide said envelope while said envelope is engagedto said seal fold cylinder.

5. Apparatus for folding the closure flap of an envelope as set forth inclaim 1 which includes,

means to rotate said delivery cylinder in a direction opposite to saidseal fold cylinder.

6. Apparatus for folding the closure flap of an envelope as set forth inclaim 2 which includes,

means to rotate said transfer cylinder and said delivery cylinder in thesame direction and said seal fold cylinder in a direction opposite tothe direction of rotation of said other cylinders.

7. Apparatus for folding the closure flap of an envelope as set forth inclaim 2 which includes,

valve means associated with said seal fold cylinder and one of saidother cylinders,

said valve means operable to apply a suction periodically through saidvacuum ports on said cylinder periphery dependent upon the relativenumber of revolutions of said seal fold cylinder to said other cylinder.

8. Apparatus for folding the closure flap of an envelope as set forth inclaim 7 in which,

suction is applied through said vacuum ports on said seal fold cylinderperiphery during every fourth revolution of said seal fold cylinder.

9. Apparatus for folding the closure flap of an envelope as set forth inclaim 1 in which,

said suction devices on said delivery cylinder include a plurality ofparallel spaced rows of vacuum ports extending longitudinally along theperiphery of said delivery cylinder, and

other valve means associated with said delivery cylinder and operable toprogressively apply suction through said spaced rows of valve ports insaid delivery cylinder periphery.

10. Apparatus for folding the closure flap of an envelope as set forthin claim 9 in which,

said other valve means includes conduit means connected to vacuum portsin said seal fold cylinder, and

means to periodically apply a suction to said valve ports in said sealfold cylinder in timed relation to the relative angular position of saidparallel spaced rows of valve ports.

1 l. A method for folding a closure flap of an envelope comprising,

engaging the leading edge of an envelope by suction to the periphery ofa transfer cylinder,

rotating said transfer cylinder to position said envelope leading edgeadjacent a buckle plate,

engaging the closure flap of said envelope by suction to the peripheryof a seal fold cylinder positioned adjacent to said transfer cylinder,

rotating said seal fold cylinder in a direction opposite to thedirection of rotation of said transfer cylinder while said closure flapportion of said envelope is engaged to the periphery of said seal foldcylinder to thereby fold said closure flap into overlying relation withthe rear surface of said envelope,

engaging said envelope body portion by suction onto the periphery ofadelivery cylinder positioned adjacent to the seal fold cylinder,

rotating said delivery cylinder in a direction opposite to the directionof rotation of said seal fold cylinder, and

releasing said envelope closure flap from the periphery of said sealfold cylinder to permit said delivery cylinder to transfer said envelopewith said closure flap folded into overlying relation with said enveloperear surface.

12. A method for folding a closure flap of an envelope comprising,

engaging the closure flap of an envelope by suction onto the peripheryof a transfer cylinder,

rotating said transfer cylinder to move said envelope between saidtransfer cylinder and a seal fold cylinder,

engaging the rear surface of said envelope adjacent said closure flap bysuction onto the periphery of said seal fold cylinder and folding saidenvelope closure flap rearwardly onto the front surface ofsaid'envelope,

rotating said seal fold cylinder in a direction opposite to thedirection of rotation of said transfer cylinder and transferring saidenvelope to a delivery cylinder positioned adjacent thereto,

engaging said rearwardly folded closure flap and said envelope frontsurface by suction to the periphery of said delivery cylinder, and

rotating said delivery cylinder in a direction opposite to the directionof said seal fold cylinder to transfer said envelope with said closureflap folded into overlying relation with the front surface of saidenvelope.

1. Apparatus for folding the closure flap of an envelope comprising, atransfer device having means to engage and convey an envelope thereon, adelivery cylinder positioned in spaced relation to said transfer device,said delivery cylinder having a plurality of suction devices extendinglongitudinally along the periphery of said cylinder, a seal foldcylinder positioned parallel to said delivery cylinder and between saiddelivery cylinder and said transfer device, said seal fold cylinderhaving a diameter smaller than said delivery cylinder, said seal foldcylinder having suction devices extending longitudinally along theperiphery of said cylinder, means to rotate said seal fold cylinder at amultiple of the angular velocity of said delivery cylinder, means torotate said delivery cylinder in timed relation to said seal foldcylinder, said seal fold cylinder suction devices arranged to engage asurface of an envelope while said envelope is engaged by said transferdevice and transfer said envelope to said delivery cylinder, and saiddelivery cylinder suction devices arranged to engage a surface of saidenvelope and transfer said envelope away from said seal fold cylinder.2. Apparatus for folding the closure flap of an envelope as set forth inclaim 1 in which, said transfer device incLudes a transfer cylinderpositioned in spaced parallel relation to said delivery cylinder, saidmeans to engage an envelope including suction devices extendinglongitudinally along the periphery of said transfer cylinder. 3.Apparatus for folding the closure flap of an envelope as set forth inclaim 1 which includes, a buckle plate positioned adjacent to said sealfold cylinder, said buckle plate having an elongated slot therein, saidbuckle plate arranged to receive and support an envelope while said sealfold cylinder engages the closure flap portion of said envelope and uponrotation of said seal fold cylinder folds said closure flap intooverlying relation with the rear surface of said envelope.
 4. Apparatusfor folding the closure flap of an envelope as set forth in claim 1comprising, a guide bracket positioned above said seal fold cylinder,said guide bracket arranged to guide said envelope while said envelopeis engaged to said seal fold cylinder.
 5. Apparatus for folding theclosure flap of an envelope as set forth in claim 1 which includes,means to rotate said delivery cylinder in a direction opposite to saidseal fold cylinder.
 6. Apparatus for folding the closure flap of anenvelope as set forth in claim 2 which includes, means to rotate saidtransfer cylinder and said delivery cylinder in the same direction andsaid seal fold cylinder in a direction opposite to the direction ofrotation of said other cylinders.
 7. Apparatus for folding the closureflap of an envelope as set forth in claim 2 which includes, valve meansassociated with said seal fold cylinder and one of said other cylinders,said valve means operable to apply a suction periodically through saidvacuum ports on said cylinder periphery dependent upon the relativenumber of revolutions of said seal fold cylinder to said other cylinder.8. Apparatus for folding the closure flap of an envelope as set forth inclaim 7 in which, suction is applied through said vacuum ports on saidseal fold cylinder periphery during every fourth revolution of said sealfold cylinder.
 9. Apparatus for folding the closure flap of an envelopeas set forth in claim 1 in which, said suction devices on said deliverycylinder include a plurality of parallel spaced rows of vacuum portsextending longitudinally along the periphery of said delivery cylinder,and other valve means associated with said delivery cylinder andoperable to progressively apply suction through said spaced rows ofvalve ports in said delivery cylinder periphery.
 10. Apparatus forfolding the closure flap of an envelope as set forth in claim 9 inwhich, said other valve means includes conduit means connected to vacuumports in said seal fold cylinder, and means to periodically apply asuction to said valve ports in said seal fold cylinder in timed relationto the relative angular position of said parallel spaced rows of valveports.
 11. A method for folding a closure flap of an envelopecomprising, engaging the leading edge of an envelope by suction to theperiphery of a transfer cylinder, rotating said transfer cylinder toposition said envelope leading edge adjacent a buckle plate, engagingthe closure flap of said envelope by suction to the periphery of a sealfold cylinder positioned adjacent to said transfer cylinder, rotatingsaid seal fold cylinder in a direction opposite to the direction ofrotation of said transfer cylinder while said closure flap portion ofsaid envelope is engaged to the periphery of said seal fold cylinder tothereby fold said closure flap into overlying relation with the rearsurface of said envelope, engaging said envelope body portion by suctiononto the periphery of a delivery cylinder positioned adjacent to theseal fold cylinder, rotating said delivery cylinder in a directionopposite to the direction of rotation of said seal fold cylinder, andreleasing said envelope closure flap from the periphery of said sealfold cylinder to permit said delivery cylinder to transfer said envelopewith said closure flap folded into overlying relation with said enveloperear surface.
 12. A method for folding a closure flap of an envelopecomprising, engaging the closure flap of an envelope by suction onto theperiphery of a transfer cylinder, rotating said transfer cylinder tomove said envelope between said transfer cylinder and a seal foldcylinder, engaging the rear surface of said envelope adjacent saidclosure flap by suction onto the periphery of said seal fold cylinderand folding said envelope closure flap rearwardly onto the front surfaceof said envelope, rotating said seal fold cylinder in a directionopposite to the direction of rotation of said transfer cylinder andtransferring said envelope to a delivery cylinder positioned adjacentthereto, engaging said rearwardly folded closure flap and said envelopefront surface by suction to the periphery of said delivery cylinder, androtating said delivery cylinder in a direction opposite to the directionof said seal fold cylinder to transfer said envelope with said closureflap folded into overlying relation with the front surface of saidenvelope.